Silicon https://doi.org/10.1007/s12633-018-9912-2
ORIGINAL PAPER
The Effect of TiO2 on the Optical and Mechanical Properties of Heavy Metal Oxide Borosilicate Glasses Yasser B. Saddeek1
· Kamal A. Aly1,2 · KH. S. Shaaban1 · Atif Mossad Ali3,4 · Mahmoud A. Sayed3
Received: 6 February 2017 / Accepted: 16 May 2018 © Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract The density, the molar volume, the rigidity, the UV reflectance and the glass transition temperatures of the x TiO2 – 20Na2 B4 O7 – 30PbO – 20SiO2 – (30-x) Bi2 O3 glass system were determined. These physical parameters were acquired by using the DTA, ultrasonic and UV techniques to explore the effect of TiO2 . The replacement of Bi2 O3 by TiO2 decreased these physical parameters, which suggested the glass modifier role of TiO2 . This attitude can be attributed to the smaller ionic radii, the density and the polarizability of TiO2 than that of Bi2 O3 . Moreover, according to the FTIR, TiO2 created non-bridging oxygens in the network that decreased the bond strength of the glass system. The decreases of the rigidity, the glass transition temperature and the optical band gap are sensitive to the decrease of the bond strength and the created nonbridging oxygens in the lead alkali borosilicate network. The obtained results were discussed in relation to the role of TiO2 in the lead borosilicate glass system. Keywords TiO2 · Heavy metal oxide glasses · Thermal analysis (DTA) · Mechanical properties · UV spectroscopy
1 Introduction Obviously, the consolidation of Bi2 O3 in various glass systems had drawn observable speculations. These glass systems are characterized by the small values of the glass transition temperatures, the high third-order nonlinearities and the special optical transparency in infrared [1–11]. On the other hand, titanium has gained importance recently for its broad range of applications in the biomedical field [12] and in the glass and glass-ceramics [13, 14]. TiO2 is
Yasser B. Saddeek
[email protected] 1
Faculty of Science, Physics Department, Al-Azhar University, Assiut 71524, Egypt
2
Physics Department, Faculty of Science and Arts Khulais, Jeddah University, Jeddah, Saudi Arabia
3
Physics Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia
4
Department of Physics, Faculty of Science, Assiut University, Assiut, Egypt
one of the first oxides to be investigated for the antitumor properties and hence it is widely used as a biomaterial for several dental and orthopedic clinical purposes. It is accepted that TiO2 can be inserted as dopants to act as a good nucleating agent, so its consolidation in a glass system is valuable in some specified glasses for electrical and optical uses. The uses depend on the ratio of the two valence states of TiO2 on one hand and the glass type, the composition and the condition of melting on the other hand. The electronic configuration of titanium ions arises out of the empt or unfille d-shell of the ions in glasses that resulted in the existence of trivalent (Ti3+ ) and tetravalent (Ti4+ ) valence states. Accordingly, Alkali borate and alkali silicate glasses favor the colorless high tetravalent (Ti4+ ) ions [15–19]. However, from the literature survey, there are numerous articles concerning heavy metal oxides (HMO) included in the network of borosilicate glasses and to the best of our knowledge, few interested articles with titanium additios in this complicated network were presented [20– 25]. The objective of this work is to characterize the role of TiO2 in HMO-alkali borosilicate glasses Na2 B4 O7 - PbOSiO2 – Bi2 O3 ) by investigating the mechanical, thermal, and optical properties.
Silicon Table 1 The nominal composition of the x TiO2 – 20Na2 B4 O7 – 30PbO – 20SiO2 – (30-x) Bi2 O3 glass system
Sample name
Chemical composition
G1 G2 G3 G4 G5
Na2 B4 O7
PbO
SiO2
TiO2
Bi2 O3
20 20 20 20 20
30 30 30 30 30
20 20 20 20 20
0 5 10 20 30
30 25 20 10 0
2 Experimental Procedures In order to prepare glass samples with the chemical formula x TiO2 – 20 Na2 B4 O7 – 30 PbO – 20 SiO2 – (30 - x) Bi2 O3 (0 ≤ x ≤ 30 mol%), convenient amounts of analytically pure grade chemicals of PbO, TiO2 , SiO2 , Bi2 O3 and Na2 B4 O7 .10H2 O were completely unsettled in an agate mortar. The mixture was melted in a ceramic crucible at 1050 ◦ C for ∼1 h to form a liquid without any bubbles. In order to accomplish homogeneity, the melt was rotated in the crucible several times. The molten was then cast into a brass mold and thereafter annealed at 400 ◦ C. The glass samples were ground and polished optically to have suitable dimensions (1.5 mm for optical measurements and 7 mm for ultrasonic measurements) with non-parallelism of the two opposite side faces less than 0.01◦ . The nominal glass compositions were listed in Table 1. X-ray diffraction (Philips X-ray diffractometer PW/1710 ˚ powered at with Ni-filtered Cu-Kα Radiation (λ = 1.542 A) 40 kV and 30 mA) was used to check the amorphous nature of the investigated glasses. A micro-DTA (SHIMADZU 50)
apparatus was used for the thermal analysis measurements with the use of powdered alumina as a reference material and ∼15 mg the powdered sample was introduced into a platinum boat and scanned over the temperature range 30– 700 ◦ C in nitrogen medium with a heating rate 20 K.min−1 . The Fourier Transform Infrared (FTIR) spectrum of one sample for example, is scanned in the range 400–1600 cm−1 on JASCO 430 (Japan) spectrometer at room temperature and with the accuracy of the measurement was about 2 cm−1 . Glass densities (ρ) were measured utilizing the notable Archimedes technique with a random error ±22 kg m−3 by considering Xylene is the immersion liquid. The molar volume of the glass was computed from the relation Vm = M/ρ, where M is the molecular weight of the glass. The random error of the molar volume was ±0.2 × 10−6 m3 mol−1 . The longitudinal (vL ) and shear (vT ) ultrasonic velocities were measured at ∼300 K with a random error ±10 m/s. The utilized transducers operated at a fundamental frequency 4 MHz along with a digital ultrasonic flaw detector (KARL DEUTSCH) were also
Fig. 1 XRD of the studied glasses
Intensity(a.u)
30 TiO2
20 TiO2 10 TiO2
5 TiO2
0 TiO2
80
70
60
50
40
2
30
20
10
Silicon
3 Results and Discussions
Absorbance (a.u)
3.1 XRD and FTIR Analysis
1600
1400
1200
1000
800
600
400
-1
Wavenumber (cm ) Fig. 2 The FTIR of the 15 Bi2 O3 – 15 TiO2 – 20 SiO2 – 30 PbO – 20 Na2 B4 O7 glass system
used. The elastic constants [26, 27] can be computed with uncertainty ±1.1 GPa utilizing the ultrasonic velocities and the density as; Longitudinal elastic moduli L = ρvL2 Shear elastic moduli G = ρvT2 Bulk modulus K = L − 4/3G Micro-hardness Y H = (1 − 2σ ) and Young’s modulus 6(1 + σ ) Y = (1 + σ ) 2G At normal incidence both the glass transmittance T (λ) and reflectance R (λ) were measured at room temperature in the spectral range 200–2500 nm utilizing a computer controlled double beam spectrophotometer (JASCO V- 670).
Neither discrete lines nor sharp peaks were revealed in the XRD curves as shown in Fig. 1. Only a hump about 30◦ demonstrated the amorphous state of the prepared glass samples was observed. This hump was shifted to higher 2θ, i.e., to higher d-spacing between the atomic levels. Thus, the glass network is expected to relax as the TiO2 content increased. Moreover, the FTIR as shown in Fig. 2 was scanned for the sample 15 Bi2 O3 – 15 TiO2 – 20 SiO2 – 30 PbO – 20Na2 B4 O7 for example to elucidate the various structural units in the explored glasses. The detailed analysis of the FTIR of the whole samples will be discussed in a further work. The observed broad bands in the figure were deconvoluted to determine the presented structural units. The small bands at 452, 519 and 693 cm−1 may be attributed to the vibrations of alkali ions [16], the vibrations of Bi – O of distorted BiO6 units [2, 5] and the vibrations of TiO6 units [13], respectively. A peak at 776 cm−1 is related to B-O-B bending vibration as a result of bridging oxygen between one tetraborate and one triangular boron atoms [18]. The band observed at 920 cm−1 is due to the symmetric stretching vibration of terminal Si – O− units [5]. This band is created due to the breaking of bonds which created non-bridging oxygen (NBO) in the glass structure. The bands around 849–1129 cm−1 are related to the stretching vibrations of tetrahedral borate units (BO4 units). The stretching mode of triangular borate groups (BO3 units) is across the bands around 1247–1544 cm−1 [18]. Bi2 O3 is an incipient glass network former and takes part octahedral positions in the glass network with BiO6 structural units. The presence of the modifiers like Na2 O and PbO in the borosilicate framework increased number of non-bridging oxygens and as a result, Bi3+ ions are incorporated in the glass network as deformed octahedral [BiO6/2 ]3− units [5]. By the integration of TiO2 to the host
Table 2 The density (ρ), the molar volume (Vm ), the sound velocities (longitudinal, vL and shear, vT ), and the elastic moduli (Shear modulus, C44 , longitudinal modulus, C11 , bulk modulus, K, Young’s modulus, Y and micro-hardness, H the glass transition temperature, Tg , the optical band gap, Eg and the Urbach’s energy (γ ) Sample name
G1 G2 G3 G4 G5
ρ
V m × 10−6
vL
(kg/m3 )
(m3 mol−1 )
(ms−1 )
4900 4700 4400 4210 4080
47.38 45.29 43.99 36.81 28.52
5984 5907 5887 5798 5753
vT
C44
C11
K
Y
H
(GPa) 3351 3308 3296 3246 3221
55.02 51.43 47.8 44.36 42.33
175.5 163.9 152.5 141.5 135.1
102.1 95.42 88.76 82.38 78.6
139.9 130.8 121.6 112.8 107.7
8.4 7.8 7.3 6.8 6.4
Tg
Eg
γ
(◦ C)
eV
eV
483 479 465 456 393
2.9 2.87 2.84 2.81 2.78
0.186 0.192 0.196 0.196 0.203
Silicon
3.2 Density and Molar Volume
44
-6
4650
40
4500 36 4350 32 4200 28
4050 0
5
10
15
20
25
30
TiO2 (mol%)
Fig. 3 Dependence of the density and the molar volume on the TiO2 content
Longitudinal ultrasonic velocity, vL (m/s)
4800
In Table 2, the ultrasonic velocities and the values of their corresponding elastic moduli (longitudinal, shear, Young, bulk and micro-hardness) are given. As shown in Fig. 4 and within the experimental error, both the ultrasonic velocities (vL and vT ) were decreased as a function of the TiO2 content and the values of (vL ) are noteworthy more than (vT ). The ultrasonic wave velocities in a medium rely on the structure, cross-link density, compactness and size of the incorporated atoms and ions [29, 30]. Lower ultrasonic wave velocities revealed the existence of non-bridging oxygens in a network. This network had low cross-link density and the strength of their chemical bonds is low. These factors deterred the transmission of the ultrasonic energy and reduced the ultrasonic velocity. Moreover, the nature of the glass modifier role of Bi2 O3 or PbO manifested itself in borate based glasses when the content didn’t exceed 50 mol% [4, 26–28]. Recent studies on bismuth borate based glasses altered with TiO2 revealed that Bi2 O3 incorporated in the glass network as deformed octahedral [BiO6/2 ]3− units and titanium ions are expected to exist mainly in Ti3+ state [6]. Accordingly, in the studied glass system as the TiO2 content increased, there is a reaction of TiO2 with B2 O3 and SiO2 . Thus it is conceivable that Ti4+ can be reduced to Ti3+ . This reaction created non-bridging oxygens associated with Si4+ and B3+ . The non-bridging oxygens in its turn decreased the cross-link density of the various structural groups and closeness of the packing which reduced the ultrasonic velocity. The acquired varieties of the elastic moduli as shown in Fig. 5 and within the experimental error revealed a comparable observation as that of the velocity. In general, the elastic moduli are influenced by the density variations of the glass in one hand and the ultrasonic velocity variations
6000 -1
Vm 48
3
4950
The molar volume, Vm x 10 ( m mol )
The density,
3
(kg/m )
The estimations of both ρ and Vm of the studied glasses were given in Table 2. The density of the base glass is determined as 4900 kg/m3 . The density is an adequate tool and it depends on the compactness and the geometrical configurations that included the coordination numbers, the cross-link densities and the dimensions of the interstitial spaces of the glass. As shown in Fig. 3 and within the experimental error, the density decreased with an increase in the content of TiO2 This decrease can be related to the replacement of Bi2 O3 which has a larger ionic radius and larger atomic weight with respect to TiO2 . Since the atomic weight of TiO2 and Bi2 O3 is considerably different, the observed decrease in the density indicated that the atomic weight change has a more important effect on the density values. Another reason for the decrease of the density that is the replacement of [BiO6 ] structural unit by [TiO6 ] as deduced from the FTIR. The density of [BiO6 ] is higher than the density of [TiO6 ] that incorporated in the decrease of the density The observed decrease of the molar volume as shown in Fig. 3 can be clarified by the change of the interatomic spacing within the glasses network since the ionic radii of Ti2+ are smaller than that of Bi3+ . Moreover the molar volume of TiO2 is smaller than that of Bi2 O3 [6, 18, 28]. These factors incorporated in the decrease of the molar volume.
3.3 Ultrasonic Velocities and Elastic Constants
5950
vT 3360 vL
5900
3320
3340
3300 5850
3280 5800
3260
5750
3240 3220
Transverse ultrasonic velocity, vT (m/s)
glass, the titanium ions occupied substitutional octahedral sites as corner sharing [TiO6/2 ]2− units [13]. The increase of TiO2 in the studied network created more non-bridging oxygens in the borosilicate network that increased the length between the different atoms and such an increase can be correlated to the increase of the d-spacing between the atomic levels as observed from XRD spectra.
5700 0
5
10
15
20
25
30
TiO2 (mol%)
Fig. 4 Dependence of the longitudinal and shear ultrasonic velocities vL and vT on the TiO2 content
Silicon
140 Young's modulus,Y (GPa)
104
K Y
100
135
96
130
92
125 88 120 84 115 80
110 105
The bulk modulus, K (GPa)
145
76 0
5
10
15
20
25
30
TiO2 (mol%)
Fig. 5 The compositional dependence of the bulk modulus (K) and Young’s modulus (Y ) on TiO2 content
on the other hand. In addition, the cation field strength of TiO2 is lower than that of Bi2 O3 . Thus, as the cation field strength of the modifier decreased, so, its ability to polarize its surroundings decreased. This process deterred the ion-dipole interaction because of the decrease of the local expansion of the network around such a modifier. In this way, as the TiO2 increased at the expense of Bi2 O3 , the polarizability of the surroundings, the coordination number, the cross-link density, the number of bonds per unit glass formula unit the bond strength and the average force constant of the explored glasses decreased. Thus, the elastic moduli decreased. On the other hand, the decrease in the moduli will be relied upon the decrease in the rigidity of the glass network and hence, prompted a lower thermal stability. Confirmation of the preceding analysis can be extracted
from the decrease of the values of the Tg of the explored glasses as a function of TiO2 , as shown in Fig. 6 [30]. It was mentioned before [31], that the values of the Tg depend on the stretching force constant and the average crosslink density. The two preceding parameters are decisive in the determination of the ultrasonic velocities and the elastic moduli.
3.4 UV-Vis Spectroscopy Analysis The spectra of the glass transmittance (T (λ)) and reflectance (R(λ)) of HMO borosilicate glasses adjusted with various concentrations of TiO2 in the spectral range 200–2500 nm are shown in Fig. 7. It was found that, the edge of the optical absorption is not sharply characterized but indicated the short range order of the prepared glasses. As represented in Fig. 7, the addition of TiO2 shifted the optical spectra to the high wavelength side (i.e., to the red shift of the optical band gap) [32, 33]. The absorption coefficient (α) as a function of the wavelength was ascertained using the following expression [34]: α(λ) = t −1 ln(T (λ)−1 (1 − R(λ)))
(1)
where t is the glass thickness. In the strong absorption range, Mott and Davids suggested the following expression for glassy materials [34]. α.hν = (hν − Eg )ι
(2)
where hν is the incident photon energy, is a band tailing parameter, Eg is the optical band gap, the exponent ι has the values of 2, 3, 1/2 and 1/3 that individually related to indirect allowed, indirect forbidden, direct allowed and
1.0 Tp
0.8
Q (a.u.)
30 TiO2 20 TiO2
T&R
Exo
Tg
T
0.6
0 TiO2 5 TiO2 10 TiO2
0.4
20 TiO2
10 TiO2
30 TiO2
Endo
0.2
R
5 TiO2 0 TiO2
100
200
300
400
500
600
700
0.0
400
800
1200
1600
2000
2400
Wavelength (nm)
Temperature ( C)
Fig. 6 DTA of the x TiO2 – 20 Na2 B4 O7 – 30 PbO – 20 SiO2 – (30 x) Bi2 O3 (0 ≤ x ≤ 30 mol%) glasses
Fig. 7 The transmittance and reflectance (T&R) spectra of x TiO2 – 20 Na2 B4 O7 – 30 PbO – 20 SiO2 – (30 - x) Bi2 O3 (0 ≤ x ≤ 30 mol%) glasses
Silicon
7.5
1.6
Eg (exp.)
0.204 0 TiO2 5 TiO2 10 TiO2
2.84 0.192
Eg (eV)
(eV)
0.196
4.5 0.8 2.7
2.8
h (eV)
2.9
3.0
5 TiO2
0.184
10 TiO2
3.0
2.80
0.188
0 TiO2
0
5
20 TiO2 30 TiO2
2.7
h (eV)
3.0
3.3
20
25
30
Fig. 9 The Eg and γ values for glasses with different TiO2 contents
Eg through the following relationship:
Fig. 8 The relation between (αhν)1/2 - photon energy (hν). The inset figure shows the relation of ln(α) - (hν) for glasses with different TiO2 contents
direct forbidden transitions. The absorption coefficient √ parameter α.hν was plotted against hν for all glasses under study as shown in Fig. 8. It was noticed that for some amorphous materials, logic fit of Eq. 2 with ι = 2 is accomplished. On the opposite side, at the low absorption region, the absorption coefficient dependence on the photon energy obeys the exponential relation [35] as: α = α0 exp(hν/γ )
15
TiO2 (mol%)
(3)
where α0 is a constant and γ is related to the width of the band tail of localized states in the conduction or valence band edge specifically the Urbach’s energy. The inset of Fig. 8 depicted the plots of ln(α) versus hν for the glasses under study. The observed decrease in Eg values, as listed in Table 2, with the increase of TiO2 content can be interpreted in terms of Mott and Davies model [35]. Figure 9 depicted the compositional dependence of both Eg and γ as a function of TiO2 content. As indicated from Fig. 9, the Eg values are inversely proportional to the localized states width(γ ) that satisfied Mott and Davies model. It was reported that the non-bridging oxygens bind excited electrons less tightens than the binding of the bridging oxygens. The increase of the TiO2 content created nonbridging oxygens and bond defects that increased the degree of localization of electrons, and consequently the donor center in the glass matrix. Accordingly, the absorption edge shifted toward the longer wavelength and the optical band gap decreased. In addition, the Eg values can be correlated with the bulk modulus (Kop ) that determined from optical measurements as stated by Aly [36, 37]. Therefore, the values of Kop of the present glasses can be correlated with the values of the
Kop = −478.93 + 200.13Eg
(4)
Furthermore, it was found that, the Eg values are correlated with the Tg values by the expression: Tg(th) = −701.87 + 403.33Eg
(5)
Figure 10 depicted the best fit with regression coefficient 0.998 for (K vs. Eg ) and (Tg vs. Eg ) for the present glassy system. On the other side, the refractive index (n) of the prepared glasses can be investigated based on the measured glass reflectance (R) and/or transmittance (T ). The well-known quadratic equation [38–40] helps one to calculate the n values at each wavelength (λ) in the used spectral range as follows: R=
(1 − n)2 + k 2
(6)
(1 + n)2 + k 2 Kop
100
The bulk modulus Kop (GPa)
2.4
10
480
Tg
470 95 460 90 450 85
440
80 75
Tg (oC)
1/2
1.2
ln( )
6.0
2.88
0.200
30 TiO2
-1
( h ) (cm eV)
1/2
20 TiO2
430
2.78
2.80
2.82
2.84
2.86
2.88
2.90
420
Eg (eV) Fig. 10 The Kop and Tg values as a function of Eg for glasses with different TiO2 contents
Silicon
5.0
30 TiO2 20 TiO2
Refractive index
4.5
10 TiO2 5 TiO2 0 TiO2
4.0 3.5 3.0
Acknowledgements The authors (Prof. Atif M. Ali and Dr. Mahmoud A. Sayed) extended his appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the research group program under grant number R.G.P. 2/8/38.
2.5 2.0
800
1200 1600 2000 Wavelength (nm)
2400
Fig. 11 The refractive index (n) as a function of the wavelength (λ) for x TiO2 – 20 Na2 B4 O7 – 30 PbO – 20 SiO2 – (30 - x) Bi2 O3 (0 ≤ x ≤ 30 mol%) glasses
where k is the extinction coefficient (k = αλ/(4π )). Due to the insignificance of the values of k, so, the values of n can be given in terms of R or T as follows; √ √ (7) n = (1 + R)/(1 − R) n=
The decrease of the rigidity was reflected in its turn from the decrease of the values of the ultrasonic wave velocities and the corresponding elastic moduli. Moreover, another reason incorporated in the decrease of the rigidity is that the created non-bridging oxygens and the bond defects. The last two physical parameters were indicated from the decrease of the optical band gap. There is a good correlation between the behaviors and values of the Eg , Tg and Kop was observed.
1 + (1 − T 2 )/T
(8)
The symbols in Fig. 11 are calculated by Eq. 7 and the solid lines in red are calculated by Eq. 8. Also, from Fig. 11 it was shown that the refractive index (n) decreased with increasing the wavelength while the n values of the studied glasses decreased with increasing of the TiO2 content. According to the Lorentz–Lorenz equation, the density of the material affected the refractive index in a direct proportion. Thus, the increase in the values of the refractive index is owing to the increase of the glass density. Furthermore, the refractive index is indirectly proportional to the molar volume, thus, the refractive index increased while the molar volume decreased.
4 Conclusions The density, the molar volume, the rigidity and the thermal properties on one hand and the UV transmission and reflection on the other hand, of heavy metal oxidesborosilicate glasses modified with different contents of TiO2 have been studied. It was observed that the relationship between the optical, mechanical and thermal properties is in excellent agreement with each other. The observed decrease in the Tg values with increasing the content of TiO2 is an indicator of the decreased rigidity of the explored glasses.
References 1. Amano M, Sakata H, Tanaka K, Hirayama T (1994) Electrical properties of Bi2O3 -SrO-V2O5 glasses and glass-ceramics. J Ceram Soc Jp 102:424–429 2. Abdel-Kader A, Higazy AA, Elkholy MM (1991) Compositional dependence of infrared absorption spectra studies for TeO2 –P2O5 and TeO–P2O5 –Bi2O3 glasses. J Mater Sci: Mater Electron 2:157– 163 3. Pascuta P, Borodi G, Culea E (2008) Influence of europium ions on structure and crystallization properties of bismuth borate glasses and glass ceramics. J Non-Crst Solids 354:5475–5479 4. Hwang C, Fujino S, Morinaga K (2004) Surface tension of Bi2 O3 -B3 O3 -SiO2 glass melts. J Am Ceram Soc 87:1677–1682 5. Molla AR, Tarafder A, Karmakar B (2016) Fabrication and properties of Nd3+ -doped ferroelectric barium bismuth titanate glass-ceramic nanocomposites. J Alloy Compd 680:237–246 6. Chen F, Yu Q, Qiao B, Dai S, Zhang Q (2016) Influence of TiO2 on thermal stability and crystallization kinetics of tellurite glasses within TeO2 –Bi2 O3 –Nb2 O5 pseudo-ternary system. J Non-Cryst Solids 404:32–39 7. ElBatal FH, Abdelghany AM, ElBatal HA (2014) Characterization by combined optical and FT infrared spectra of 3d-transition metal ions doped-bismuth silicate glasses and effects of gamma irradiation. Spectrochim Acta A 122:461–468 8. Ramadan RM, Abdelghany AM, ElBatal HA (2017) Gamma rays interactions with bismuth phosphate glasses doped with 3d transition metal oxides. Silicon. https://doi.org/10.1007/s12633-0169545-2 9. Hammad AH, Abdelghany AM, ElBatal HA (2017) Thermal, structural, and morphological investigations of modified bismuth silicate glass-ceramics. Silicon 9:239–248 10. Chen Q, Ma HQ, Wang H, Chen QP (2015) Structural and properties of heavy metal oxide Faraday glass for optical current transducer. J Non-Cryst Solids 429:13–19 11. Syam Prasad N, Varma KBR (2003) Structural and dielectric properties of ferroelectric Sr1−x Bax Bi2 (Nb0.5 Ta0.5 )2 O9 and Sr0.5 Ba0.5 Bi2 (Nb1−y Tay )2 O9 ceramics. Mater Res Bul 38:195–206 12. Samudrala R, Abdul Azeem P, Penugurti V, Manavathi B (2017) Cytocompatibility studies of titania-doped calcium borosilicate bioactive glasses in-vitro. Mater Sci Eng C 77:772–779 13. Molla AR, Tarafder A, Karmakar B (2011) Synthesis and properties of glasses in the K2 O–SiO2 –Bi2 O3 –TiO2 system and bismuth titanate (Bi4 Ti3 O12 ) nano glass–ceramics thereof. J Mater Sci 46:2967–2976 14. De Sousa NCA, De Araujo MT, Jacinto C, Vermelho MVD, Dantas NO, Santos CC, Guedes I (2011) The role of TiO2 in
Silicon
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26. 27.
the B2 O3 –Na2 O–PbO –Al2 O3 glass system. J Solid State Chem 184:3062–3065 Hammad AH, Abdelghany AM, Elbatal HA (2016) The influence of titanium ions on crystallization, morphological, and structural properties of strontium borate glass. J Non-Cryst Solids 450:66–74 Abdelghany AM, ElBatal HA (2013) Effect of TiO2 doping and gamma ray irradiation on the properties of SrO–B2 O3 glasses. J Non-Cryst Solids 379:214–219 Zhu X, Li Q, Ming N, Meng Z (1997) Origin of optical nonlinearity for PbO, TiO2, K2O, and SiO2 optical glasses. Appl Phys Lett 71:867. https://doi.org/10.1063/1.119672 Doweidar H, El-Egili K, Ramadan R, Al-Zaibani M (2017) Structural units distribution, phase separation and properties of PbO–TiO2 –B2 O3 glasses. J Non-Cryst Solids 466–467:37–44 Cunha DL, Kuznetsov A, Achete CA, Machado AEH, Marques M (2018) Immobilized TiO2 on glass spheres applied to heterogeneous photocatalysis: Photoactivity, leaching and regeneration process. PeerJ 3:e4464 Elbashar YH, Rashad MM, Rayan DA (2018) Physical and mechanical properties of neodymium doped zinc borate glass with different boron content. Silicon 10:115–122 Dahiya S, Punia R, Murugavel S, Maan A (2014) Concentration dependence of intensity parameters and radiative properties of Sm3+ ions doped in BaO–ZnO–B2 O3 glasses. Indian J Phys 88:1169–1173 Kaur R, Singh S, Pandey O (2013) Influence of CdO and gamma irradiation on the infrared absorption spectra of borosilicate glass. J Molc Struct 1049:409–413 Yamamoto Y, Hashimoto T, Nasu H, Hashimoto T, Kamiya K (2002) Second Harmonic Generation from CsLiB6 O10 Containing Glass-Ceramics. J Mater Res 17:3110–3116 Rezvani M, Eftekhari Yekta B, Marghussian M (2005) Utilization of DTA in determination of crystallization mechanism in SiO2 – Al2 O3 –CaO–MgO (R2 O) glasses in presence of various nuclei. J Eur Ceram Soc 25:1525–1530 FaeghiNia A, Marghussian VK, TaheriNassaj E (2007) Effect of B2 O3 on crystallization behavior and microstructure of MgO– SiO2 –Al2 O3 –K2 O–F glass–ceramics. Ceram Int 33:705–894 Saddeek Y, Abd El Latif L (2004) Effect of TeO2 on the elastic moduli of sodium borate glasses. Physica B 348:475–484 Saddeek YB, Yahia IS, Aly KA, Dobrowolski W (2010) Spectroscopic, mechanical and magnetic characterization of some
28.
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31.
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38. 39.
40.
bismuth borate glasses containing gadolinium ions. Solid State Sci 12:1426–1434 Shaim A, Et-tabirou M, Montagne L, Palavit G (2002) Role of bismuth and titanium in Na2O-Bi2O3-TiO2-P2O5 glasses and a model of structural units. Mater Res Bull 37:2459–2466 Gerlich D, Wolf M, Yaacov L, Nissenson B (1976) Thermoelastic properties of ULE®Titanium silicate glass. J Non-Cryst Solids 21:243–249 Gayathri Devi AV, Rajendran V, Jeyasubramanian K, Suresh Kumar N, Abdel-Hameed SAM (2006) Ultrasonic investigation on nanocrystalline barium borate (BBO) glass ceramics. Synth React Inorg Met-Org Nano-Met Chem 36:215–219 EL-Mallawany R, Hager IZ, Poulain M (2002) Thermal properties of new molybdenum oxyfluoride glasses. J Mater Sci 37:3291– 3297 Aly KA (2010) Optical band gap and refractive index dispersion parameters of Asx Se70 Te30− x (0 = x = 30 at.%) amorphous films. Appl Phys A 99:913–919 Aly KA (2009) Optical properties of Ge–Se–Te wedge-shaped films by using only transmission spectra. J Non-Cryst solids 355:1489–1495 Othman AA, Aly KA, Abousehly AM (2007) Effect of Te additions on the optical properties of (As–Sb–Se) thin films. Thin Solid Films 515:3507–3512 Davis EA, Mott NF (1970) Conduction in non-crystalline systems V. Conductivity, optical absorption and photoconductivity in amorphous semiconductors. Philos Mag 22:903–922 Aly KA, Dahshan A, Abousehly AM (2008) Compositional dependence of the optical properties of amorphous Se100− x Tex thin films. Philos Mag 88:47–60 Aly KA (2015) Discussion onthe interrelationship between structural, optical, electronic and elastic properties of materials. J Alloy Compd 630:178–182 Saddeek YB, Aly KA, Bashier SA (2010) Optical study of lead borosilicate glasses. Physica B 405:2407–2412 Saddeek YB, Aly KA, Dahshan A, Kashef IME (2010) Optical properties of the Na2 O-B2 O3 -Bi2 O3 -MoO3 glasses. J Alloy Compd 494:210–213 Aly KA, Saddeek YB, Kashef IME (2017) Physical characterization of Titania modified sodium borate glasses. J Optoelectron Adv Mater 19:623–628
